Mechanism for observing nozzle spray patterns



March 19, 1963 K. A. DOMEISEN MECHANISM FOR OBSERVING NOZZLE SPRAY PATTERNS Filed Feb. 12, 1960 INVENTOR.

KARL A. DOMEISEN. wwfigfl j %'ORNEYS.

fiblfifi Patented Mar. 19, 1%53 ice 3,081,623 MECHANISM F65"; @BSEEVING NGZZLE SPRAY FATTERNS Karl A. Dorncisen, Marblehead, Mass, assignor to Avco Corporation, a corporation of Delaware Filed Feb. 12, 1960, Ser. No. 8,354 1 Claim. (Cl. 73-=-ll19) This invention relates to mechanism for visual observation of the spray patterns produced by nozzles used in fuel injection equipment for diesel engines as well as other so-called fuel injection systems used with other types of internal combustion engines.

In order to visually observe the effectiveness of a fuel injection nozzle under actual operating conditions, various mechanisms have been used in the past, some of them related to transparent walls in the cylinder head of the engine adjacent the combustion chamber so that the spread or pattern of the spray ejected from a nozzle may be visually observed or photographed. Such devices have difficulty in practical application and it is a primary object of this invention to provide a mechanism whlch will simulate engine conditions and result in a separate test device which will have less complications while still producing the desired results.

Specifically, it is the purpose of the invention to use mechanism providing for the ejection of liquid fuel from a nozzle into a liquid filled chamber having transparent walls so that the nozzle spray pattern may be observed or photographed. The liquid under a relatively low pressure head simulates the relative density relationship existing between the fuel injected by the nozzle and the air under compression in the cylinder head of an engine at the time of fuel injection, when the nozzle is actually in use.

The above and other objects of the invention will appear more fully from the following more detailed description and by reference to the accompanying drawings forming a part hereof and wherein:

FIG. 1 is a view of the assembled mechanism including a chamber with transparent Walls for containing liquid such as diesel fuel to which is connected a nozzle unit where the fuel spray is to be observed, and showing a light source and camera in position.

FIG. 2 is an end view of the mechanism looking into the transparent wall of the chamber.

FIG. 3 is a section on line 3-3 of FIGURE 2.

FIG. 3a is a section like FIG. 3 but shows a modified form of assembly of parts providing a smaller chamber.

Referring to the drawings, a chamber 10, in practice about 5" in diameter by 2 /2 in width, with transparent Lucite Walls 12 and 14 held in place by annular retaining members 16 and 18, bolted to an annular spacing member 20 as shown. There is thus provided a chamber with transparent walls 12 and 14 with relatively narrow spacing so that light can pass through the unit and the interior thereof can be observed by placing a light on one side of the unit and a camera on the other side for photographic or visual observation as may be desired. If necessary, the Width of the chamber as shown in FIG. 3 can be reduced by reversing the annular retaining members 16 and 18 together with the transparent walls 12 and 14 as indicated in FIG. 3a. Provision is made in the annular spacing member 20 for supporting the nozzle 22 of a fuel injection unit 24 to be inserted and positioned just inside the chamber as shown. At the top of the chamber, an outlet 2 26, preferably about /2 ID. pipe, is provided which serves as an overflow and can be connected to a liquid column 26a which will make it possible to observe and control the fluid pressure head of the liquid contained in the chamber.

Referring to FIGS. 1 and 3, a light funnel 28 is provided which extends about two feet from one side of the chamber 18 and a stroboscopic flash light 39 or other light source illuminates the chamber through the light funnel 2,8. A camera 31. is positioned on the opposite side of the chamber and is connected to take photographic record of the chamber.

In operation, the chamber 16 is filled with diesel fuel or the fuel which is being used in the nozzle to be tested and the liquid pressure in the chamber is maintained at a definite head on the liquid in the chamber to simulate the conditions desired. As an example, a 7 /2" fuel column 26a acting on the fuel in the spray chamber it} simulates the conditions existing when a fuel injection system injects fuel into air in an engine combustion chamber under a pressure of 600 to 700 p.s.i.g. In other words, a greater density of the liquid under a 7 /2 head provides a density relation between the injected fuel and the liquid in the chamber simulating the relation which exists between the injected fuel and compressed air in the cylinder of an engine at 600 p.s.i.g. The difference in pressure between the injected fuel and the liquid fuel in the chamber makes it possible to make use of the resulting difference in density to cause a refraction of the light from source 30 through the transparent walls 12 and 14 to make the spray pattern of the injected fuel visible. "It is thus possible to observe and photograph the flow pattern produced when fuel is ejected from the nozzle into the liquid and the resulting pattern will be comparable with the pattern which can be expected in the chamber of the cylinder of an engine at the time fuel is injected.

The invention has been described by reference to an illustrative structure found practical in actual use but modifications are intended within the scope of the following claims.

I claim:

In a mechanism for simulating the conditions in an internal combustion engine cylinder suitable for observation of spray patterns of liquid fuel from a fuel injection nozzle, a quantity of liquid fuel, a chamber serving as a container for said quantity of said liquid fuel, spaced parallel transparent walls for said chamber, means for mounting said fuel nozzle extending into said chamber and extending between said transparent walls, a liquid inlet connection into said chamber, means connected with said inlet for placing said liquid fuel in said chamber under a definite pressure head, mechanism to cause liquid fuel to be ejected from said nozzle into the liquid under pressure in said chamber, thereby to simulate a relationship of ejection pressure to density simulating relative conditions in an internal combustion engine cylinder but with a relatively low pressure head on said quantity liquid fuel in said chamber.

OTHER REFERENCES N.A.C.A. Report No. 274, by Edward G. Beardsley, 1927, (pages 361-364 relied on, copy in Scientific Library). 

